1. Field of Invention
The invention relates to a fixture for aligning or working a web of material which is fed from a storage area across a driven drum forming a processing surface and which from there reaches a receiving arrangement which is placed lower than the drum.
2. Brief description of the prior art
In a known device of this type (German Published, Patent Application DE-OS 32 40 910), processing of a web material takes the form of a printing operation, performed by a print head which can be moved back and forth parallel to the axis of rotation of the drum. In this case the web material to be processed reaches the drum from a supply roller, which constitutes a storage area. From the supply roller, the web material is fed via a loop area and a guide roller to a take-up roller, which constitutes a receiving arrangement. In this known device the drum as well as the supply roller and the take-up roller are driven. Driving of the rollers and drum is required to roll off more or less web material from the supply roller, depending on the size of the loop of material web between the supply roller and the drum, and is determined by a sensor. Driving the rollers also will wind on the take-up roller more or less web material, depending on the size of the loop of material web between drum and take up-roller. In either case it must be assured that there a sufficiently large loop on both sides of the drum, so that there is always sufficient web material is available during different directions of drum rotation in the course of the printing operation. Therefore, the known device is structurally complicated, because it not only requires a driven supply roller and a driven take-up roller, but also additional control devices for the roll-off and wind-up operations.
It should also be mentioned a device of the known type is not only used to print a material web in the fashion of a drum-type plotter. For example, it is possible to use a cutting head in place of a printing head for cutting foil material which is in the shape of a web, such as material where the plastic foil portion has been provided with a layer of adhesive which in turn is covered with a removable material layer. It is possible to cut out areas from the plastic foil by cutting down to the protective layer, in order to make stick-on signs or displays.